Loading system for fork lift truck



y 7, 1964 c. P. KOLTHOFF, JR 3,140,075

LOADING SYSTEM FOR FORK LIFT TRUCK Filed Aug. 22, 1962 3 Sheets-Sheet 1July 7, 1964 c. P. KOLTHOFF, JR 3,140,075

LOADING SYSTEM FOR FORK LIFT TRUCK Fi] .ed Aug. 22, 1962 3 Sheets-Sheet2 y 7, 1964 c. P. KOLTHOFF, JR 3,140,075

LOADING SYSTEM FOR FORK LIFT TRUCK Filed Aug. 22, 1962 5 Sheets-Sheet 3United States Patent 3,140,075 LOADING SYSTEM FOR FORK LIFT TRUCK C.Paul Kolthotf, Jr., Naperville, Ill., assignor for InternationalHarvester Company, Chicago, 111., a corporation of New Jersey Filed Aug.22, 1962, Ser. No. 218,739 2 Claims. (Cl. 2542) This invention relatesin general to material handling apparatus, and more particularly to anew and improved fork lift truck.

In the material handling field it is well known to employ a lift truckhaving a vertically movable fork secured to the front portion thereof.Such machines have commonly employed relatively complex mechanical orhydraulic systems to effect the raising and lowering of the fork. It hasalso been conventional practice to provide such ma chines with intricateelectrical systems to control the actuation of the aforementionedmechanical and hydraulic lifting means. As can be readily understoodsuch known devices were not only extremely complicated, but they werealso expensive to manufacture and operate. It is, therefore, a principalobject of the present invention to provide a fork lift truck which willfunction effectively to lift pallets and the like, yet which is formedof a relatively simple design which is inexpensive to manufacture andmaintain.

Another object of the present invention is to provide a fork lift truckwhich obviates the necessity of providing a mechanical or hydrauliclifting means and an electrical control circuit therefor.

A further object of the invention is the provision of a lift truck inwhich the lifting fork is formed integrally with the truck frame, sothat the lifting fork is raised and lowered into and out of loadcarrying position by the movement of the truck frame relative to theground.

Still another object is to provide a lift truck of the type hereinafterdescribed in which the raising and lowering of the truck frame isaccomplished by varying the size of the frame supporting means.

A still further object of the invention is the provision of a lift truckhaving a lifting fork formed integrally with the frame thereof, andwhich fork is raised and lowered with respect to the ground by inflatingand deflating the ground engaging tires of the vehicle.

Yet another object of the present invention is to provide, in a lifttruck of the type hereinafter described, an air supply and control meanswhich is effective to inflate and deflate the supporting tires of thevehicle frame.

Other objects and advantages of the invention will hereinafter becomemore apparent from an examination of the following description of theannexed drawings which illustrate a preferred embodiment, and wherein:

FIGURE 1 is a side elevational view showing the lift truck in thetransport position;

FIGURE 2 is a side elevational view similar to FIG- URE l, but showingthe lift truck in the loading position;

FIGURE 3 is a plan view of the apparatus set forth in FIGURE 1 andFIGURE 2 with certain parts broken away for clarity;

FIGURE 4 is a detail view on an enlarged scale, partly in section, of aground engaging steering wheel of the present invention;

FIGURE 5 is a view partly in section of the control valve of the presentinvention;

FIGURE 6 is a view taken along the line 66 of FIG- URE 5; and

FIGURE 7 is a view similar to FIGURE 5 but showing the plunger in adifferent position.

Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the several views, thenovel lift truck of the present 3,140,075 Patented July 7, 1964invention is indicated in its entirety by reference numeral 10 in FIGURE1 through FIGURE 3. Truck 10 may be formed of any conventionalconstruction, and in the illustrated embodiment includes a body 11mounted upon a fore and aft extending frame 12. Lifting fork 13,consisting of spaced-apart prongs 14 and 15, is formed integrally withframe 12, and extends forwardly of body 11. Body 11 is supported byspaced-apart pairs of pneumatic tires 16-17 and 18-19 which arerotatably mounted on frame 12.

The means by which truck 10 is propelled are illustrated schematicallyin FIGURE 3, and include an engine 20 mounted upon frame 12. A fore andaft extending drive shaft 21 is drivingly associated with front axle 22by differential means 23, as is well known in the art. The steering ofthe vehicle is effected by linkage means, not shown, associated withsteering wheel 5 and rear wheels 18 and 19.

The air supply means by which tires 16-19 are inflated and deflated arealso illustrated schematically in FIGURE 3, and include a compressor 24of any conventional construction driven by a V-belt 25 or the like.Compressor 24 communicates with an air reservoir 26, which in turncommunicates with a circuit pressure regulator 27. It should beunderstood that while the invention has been illustrated as utilizing acompressor 24 to provide a source of air to reservoir 26, the compressoris not necessary if the reservoir can be recharged periodically from anexternal source of compressed air, such as, a shop air system. Conduit28 communicates with regular 27 and conveys air from the reservoir 26 toa three-way valve 30 which meters the air into the front and rear tires,and to a pressure gauge, not shown.

. The construction of valve 30 will be best understood from anexamination of FIGURE 5 through FIGURE 7. Valve 30 includes a body 31secured to frame 12 by bolts 32 or the like. A plunger 33 having widenedend portions 34 and 35 and a narrowed central stern portion 36 isslidably mounted within bore 37 provided in body 31. Narrowed endportion 34 of plunger 33 is provided with an apertured lug 38 in whichthe bent end portion of actuating rod 39 is pinned. Actuating rod 39 issecured to handle 40, which in turn is pivotally mounted upon steeringcolumn 41.

Valve body 31 is provided with four threaded openings 42-45 whichcommunicate with bore 37. Fittings 46-49 are threadably received withinopenings 42-45. As can be best understood from FIGURE 5, openings 43-45are disposed in substantially the same plane, which is spaced apart fromopening 42. Conduit 28 is threadably associated with fitting 46, andcompletes the pneumatic circuit from the air supply source to valve 30.Conduits 50 and 51, which are associated with fittings 47 and 48, leadto the rear and front wheels respectively. Conduit 52 which isassociated with fitting 49 leads to a pressure gauge, not shown, whichmay be any conventional design. With reference to FIGURE 3 it will benoted that T connections 53 and 54 are provided in conduits 50 and 51 todirect the air through conduits 55-58 to the individual tires.

It will be readily understood that as handle 40 is raised, plunger 33 islowered within bore 37. When handle 40 is raised to a position whereenlarged valve portion 35 passes openings 43-45, air will flow intovalve 30 from the air supply source through opening 42, and then throughopenings 43 and 44 to the front and rear wheels. When it is desired todeflate the tires, handle 40 is lowered to a position where enlargedportion 35 passes openings 43-45, thus exposing openings 43-45 toatmospheric pressure, as is shown in FIGURE 7.

The means by which the air is communicated into the individual tires isset forth in detail in FIGURE 4. While 3 FIGURE 4 illustrates only onesteering wheel 18, it should be pointed out that the structure of theother steering wheel 19 is identical, and the structure of drivingwheels 16 and 17 is substantially identical, except that wheels 16 and17 are splined to the front axle.

The rear axle 60 of lift truck is provided with an end portion ofreduced diameter 61. Hub 62 is rotatably mounted upon axle 60 bybearings 63, 64 and 65. Axle section 61 is provided with an end portion66 of further reduced diameter which is threaded to receive bearingretainer 67. Housing 68 surrounds the aforementioned axle structure, andis secured to hub 62 by a plurality of bolts 70, only one of which isshown, which also serves to secure flanges 73 and 74 of tire rimsections 71 and 72 to hub 62. Rim sections 71 and 72 are provided withannular lip portions 75 and 76, which grip the inwardly extending endsof tire 18 in air sealing relation.

Swivel means indicated generally at 78, are provided in the open endportion of housing 68 to accommodate conduit 55. Swivel means 78 includea shaft member 79 having an internally threaded opening for reception ofthe externally threaded portion of L-shaped fitting 80 which is providedon the end of conduit 55. Fitting 80 is provided with a portion ofreduced diameter 81 having a plurality of openings 82 therein, whichcommunicate with radially extending openings 83 formed in shaft portion79. An annular ring 84 is mounted in the open end of housing 68 and isrotatably mounted upon shaft 79 by bearing 85. Spaced apart shaft seals86 and 87 are provided between shaft 79 and ring 84, to define anannular chamber 88. A threaded opening 89 extends through the side wallportion of housing 68 and ring 84 and communicates with chamber 88. Aconduit section 90 is provided at one end with a threaded fitting 91which is received in opening 89 and communicates with chamber 88. Theother end of conduit section 90 is affixed to nipple 92 which isprovided in the tire rim section 71. It can be readily understood thatair is conveyed through conduit 55, fitting section 81, and into chamber88, and from there through conduit section 90 into the interior of tire18. It should also be apparent that swivel means 78 enables conduit 55to remain relatively stationary while tire 18 is free to rotate withrespect to frame 12.

In operation the operator drives the lift truck in the transport or loadcarrying position illustrated in FIG- URE 1 up to a load L mounted upona pallet P. He then lowers handle 40, thus raising plunger 33 withinvalve 30 so as to expose openings 43 and 44 to atmospheric pressure.This allows the air to escape from tires 16-19, and the weight of thevehicle will cause the lift truck to assume the loading positionillustrated in .4 FIGURE 2. The operator then drives the lift truckforward into the position indicated at 10' in FIGURE 2 with the tires ina partially deflated condition. The operator then raises handle causingplunger 33 to move downward within valve 30, thus again exposingopenings 43 and 44 to the source of air entering through opening 42. Theair is then communicated to tires 16-19 through conduits -58 and palletP is lifted from the ground into a load carrying position. When the lifttruck is transported conduits 55-58 remain in a relatively stationaryposition because of the swivel connection with the various axlehousings.

Thus it can be readily understood that what has been provided is a lifttruck of relatively simple design, yet which functions effectivelywithout the necessity of complex hydraulic, mechanical, or electricalstructure. It should also be understood that the foregoing disclosurerelates to only a preferred embodiment of the invention and thatnumerous modifications or alterations may obviously be made thereinwithout departing from the spirit and the scope of the invention as setforth in the appended claims.

What is claimed is:

l. A mobile fork lift truck comprising, in combination,

(a) a frame integrally connected to a load-carrying fork, said forkextending forwardly of said frame,

(b) a plurality of inflatable and rotatable tires positioned for movablysupporting said frame, said tires having a substantially large radialcross-section,

(0) power means disposed on the rearward portion of said frame andconnected to said truck in propelling relation,

(0.) a source of fluid under pressure mounted on said frame,

(e) and a control valve with fluid conduit means connected to saidsource and said tires for controllably inflating and deflating saidtires whereby said fork is raised into a load-carrying position andalternately lowered into load-receiving position respectively.

2. The combination set forth in claim 1 wherein said conduit meansincludes a fluid swivel passage communicatively connected to each ofsaid tires.

References Cited in the file of this patent UNITED STATES PATENTS Re.24,272 Albee Feb. 12, 1957 899,582 Weston Sept. 29, 1908 1,237,309Dewald Aug. 21, 1917 2,795,346 Farmer June 11, 1957

1. A MOBILE FORK LIFT TRUCK COMPRISING, IN COMBINATION, (A) A FRAMEINTEGRALLY CONNECTED TO A LOAD-CARRYING FORK, SAID FORK EXTENDINGFORWARDLY OF SAID FRAME, (B) A PLURALITY OF INFLATABLE AND ROTATABLETIRES POSITIONED FOR MOVABLY SUPPORTING SAID FRAME, SAID TIRES HAVING ASUBSTANTIALLY LARGE RADIAL CROSS-SECTION (C) POWER MEANS DISPOSED ON THEREARWARD PORTION OF SAID FRAME AND CONNECTED TO SAID TRUCK IN PROPELLINGRELATION, (D) A SOURCE OF FLUID UNDER PRESSURE MOUNTED ON SAID FRAME,(E) AND A CONTROL VALVE WITH FLUID CONDUIT MEANS CONNECTED TO SAIDSOURCE AND SAID TIRES FOR CONTROLLABLY INFLATING AND DEFLATING SAIDTIRES WHEREBY SAID FORK IS RAISED INTO A LOAD-CARRYING POSITION ANDALTERNATELY LOWERED INTO LOAD-RECEIVING POSITION RESPECTIVELY.